99 cavalier - the fuel gauge doesnt read accurately and it jumps

If the guage is reading but not accurately it may be the incorrect fuel pump for the vehicle or the float is may not be in the retaining clip all the way. Also possible that the float got bent during installation. Can you describe what the guage is doing such as reading full when its 1/2 full or jumping around on you?

Buick dealers have a diagnostic box that checks gauge sweep and range, an 0-100 Ohm variable potentiometer with key on can check this gauge however you must tap into the wire going for the sending unit at the tank. With a voltage meter check the four wire connection (only one)connector going to the top of the tank, find a good ground and check for voltage one will be 12 volts with KEY ON ENGINE OFF look for a 12 volt reading for 5 seconds and then it will stop this is for priming fuel rail and is to fuel pump, you want the ground side of the gauge the other two will be grounds, fuel pump and gauge. The grounds may be near the wiring harness going to the frame. In either case they will be grounds you are looking for the one that is not either ground or power, most likely it will be either a flashing light or very low voltage. Attach the pot to the gauge wire and have someone watch the fuel gauge if it is erratic the gauge is the problem. If the gauge sweeps slow and steady the problem is in the sending until in the tank. AND HAS TO BE DROPPED! Run the tank down on fuel as low as you dare and drop tank. Be carefull working with fuel can be very DANGEROUS if you are not experienced working around fuel DON'T Attempt!

In a case like this, the culpret is most likely the fuel level sending unit, which is located on the fuel pump in the fuel tank. In most vehicles, the pump and the sending unit all come in one assembly, which means in order to get a correct reading on the gauge, you'll need to replace the fuel pump. And actually, considering the fact that you have to drop the fuel tank and remove the pump anyway, it's just good measure to change them as a set.

I hope this helps! :)

you have a bad sending unit ,its inside the fuel tank,you have too drop the tank too replace it!!

Gas gauge jumping around usually implies fuel level sensor in tank is going bad...Usually if the gauge in dash is going bad will read empty or at various positions depending on fuel level in tank..Electrical short problem in gauge usually affects other gauges in cluster

The fuel level sensor is bad. The tank will have to be taken down to replace the level sensor. There is little fingers on the resistor that wear down and loose contact causing the gage to read incorrectly.

having a promblem getting starter top bolt out

The fuel pump as a gage sender that monitors the gage in the dash. I would replace the fuel pump .
Very common problem

Good Luck

Hi, this is being caused by a malfunctioning sending unit that is locate inside of the tank and is part of the fuel pump assembly. replacing the sending unit will fix this issue.

Please rate and god bless:)

you need to find the fuel pressure release around the fuel rail press the little tab when the car dies. If there is no fuel coming out from that point, your fuel pump is going.